Refrigerating apparatus



June 1, 1937, A. PHILIPP 2,082,549

' REFRIGERATING APPARATUb I Filed Aug. 14, 1934 2 Sheets-Sheet 1 I l I l y l INVENTOR. l 7 J Lnwemcz f2. PHIL/PP ATTORNEYj REFRIGERATING APPARATUS Filed Aug. 14, 1934 2 Sheets-Sheet 2 INVENTOR. LflW PLWCIS 19. PHIL/PP v kwva w ATTORNEY.

Patented June 1, 1937 UNITED STATES PATENT OFFICE Lawrence A. Philipp,

Detroit, Mich., assignor to Kelvinator Corporation, Detroit, Mich., a corporation of Michigan Application August 14,

12 Claims.

The present invention relates to multiple refrigerating systems and particularly to systems of the type employing a plurality of evaporators which are connected to a common condensing 5 mechanism.

One of the objects of the present invention is to provide an improved refrigerating system employing a plurality of evaporators in which one of the evaporators receives the liquid refrigerant from the other and in which the flow of refrigerant to the evaporators is controlled in accordance with the condition of the refrigerant in one of the evaporators. A further object of the present invention is 15 to provide a system of the above type in which the condition of the refrigerant in the evaporator last to receive liquid refrigerant is utilized for controlling the flow of liquid refrigerant to the evaporators.

Another object of the present invention is to provide an improved refrigerating system employing a plurality of evaporators of the type in which one evaporator is connected in series circuit relation with the other and in which each evaporator is provided with its individual suction line and to provide mechanism for preventing liquid refrigerant from entering the condensing mechanism through one of the suction lines and to control the quantity of liquid refrigerant delivered to the evaporators in accordance with the condition of the refrigerant in the outlet of the other evaporator.

A still further object of the present invention is to provide a refrigerating system employing 35 two evaporators, a valve between these evaporators, for causing a difi'erential in temperatures and in order to prevent an excessive quantity of liquid refrigerant in the evaporator first to receive liquid refrigerant, to provide a by-passing 40 means around the interposed valve which is operated in response to an excessive quantity of refrigerant in the evaporator first to receive liquid refrigerant.

The invention itself, however, both as to its 45 organization and its method of operation, to-

gether with additional objects and advantages thereof, will best be understood from the following description of specific embodiments, when read in conjunction with the accompanying 50 drawings, in which:

Fig. l is a schematic view diagrammatically representing a two temperature refrigerating system arranged in accordance with my invention; and

Fig. 2 is a similar view showing a second embodiment of my invention.

Referring more particularly to Fig. 1 of the drawings, the apparatus comprises a high temperature refrigerating coil I and a low tempera- 6 ture coil 2 which are so connected into a refrig- 1934, Serial No. 739,747 (Cl. 62-115) crating system that they are maintained at different temperatures by a liquid refrigerant which is supplied from condensing means comprising a double suction pressure compressor 3 and a condenser 4. The refrigerant passing from the compressor through the condenser 4 gives up its latent heat of vaporization and passes as a liquid througha feed line 5 to a liquid receiver 6 and thence to a needle valve 1 which controls its admission to the system, in a manner to'be subsequently set forth.

The refrigerantpasses from the needle valve 1 through a conduit 8 to the high temperature coil l and thence into a float valve chamber II. The liquid refrigerant passes through the float valve chamber II and thence by conduit means l2 to a weighted pressure reducing valve l3, from the outlet of which the refrigerant passes through a conduit M to the low temperature coils 2. The refrigerant while passing through the high temperature coils I is maintained at a higher pressure than in the lower temperature coils by the weighted pressure reducing valve I 3 interposed therebetween. Consequently the refrigerant in the low temperature coils 2 vaporizes at a lower pressure to maintain a lower-degree of temperature than in the high temperature coils I. It will be understood that both of the cooling coils may be provided with heat conductive fins 9 to increase their heat absorbing capacity andthey may be enclosed in suitable heat insulating compartments III as indicated by dotted lines.

From the low temperature coils 2 the refrigerant vapor passes through a conduit l6 into a housing I! which encloses a cup shaped float member l8 for actuating the needle valve 1 to control the admission of liquid refrigerant to the system through the high temperature coil I. The needle valve float housing I! is connected to the low pressure side of the high suction cylinder 2| of the compressor by means of a conduit 22 connected through the needle valve cover 23 to a pipe 24 the lower open end of which extends downwardly from the cover 23 into the cup l8 adjacent the bottom thereof.

From the top of the float valve chamber II a medium pressure suction line 21 is connected to the low pressure side of the second cylinder 28 of the compressor. The outlet of the float valve is' connected through a by-passing conduit 3! to the line H between the pressure reducing valve and the low temperature coil. This serves to discharge the liquid refrigerant from the float valve chamber ll around the pressure reducing device l3 whenever it exceedsa predetermined level in the float valve chamber thus preventing the passage of liquid refrigerant into the medium suction line 21.

The needle valve 1 is enclosed in a valve chamber 31 which is supported from the valve cover 23 and it is actuated to regulate the admission of liquid refrigerant by a valve lever 36 which is pivotally joined at one end to the valve needle I and has its other end projecting from the needle valve chamber 31 through a lateral extension 33 thereon,

The valve lever 36 is pivoted on a pivot pin 36 which extends through the valve chamber extension 38. The extended portion of the lever 36 passes through the head 42 of a tilting flexible metal bellows 43 to which it is hermetically sealed. The edges of the flexible bellows 42 are secured to the outer edges of the valve chamber extension 36 in hermetically sealed relation whereby the valve lever 36 may be tilted to actuate the valve I within the chamber 31 while maintaining hermetically sealed relation.

The cupshaped float member 18 within the valve housing is preferably of light gauge sheet metal and it functions as a float as it is buoyed up by the liquid refrigerant entering the housing II. In order to actuate the valve lever 36, in accordance with the movements of the cup float l6, a float lever 45 is pivotedly connected thereto by a pivot pin 46 which extends across the open end of the cup I 6. The other end of the float lever 46 is connected through a link 41 to the free end of the valve lever 36. In order that the vertical movements of the cup I8 may actuate the float lever 45 the'latter is pivoted in an intermediatepoint upon a pivot pin 46 which is rigidly mounted in a bracket 49 depending downwardly from the valve cover 23 which covers the valve housing l1.

It will be apparent that liquid refrigerant en;- tering' the needle valve housing i1 will cause the'cup shaped float l6 to rise thereby rotating both the float lever 46 and the valve lever 36 clockwise, thus lifting the valve needle I to engage its seat and restrict the admission of liquid refrigerant to the system. Lubricating oil in the system being lighter than the refrigerant bubbles over the edge of the cup float l3 without actuating it to close the needle valve. As the oil enters the cup 18 it is drawn up the suction pipe 24 and returns to the compressor which may be provided with an oil drain 50 in the intake manifold for draining the oil into the crank case. During the operation of the system if the liquid refrigerant in the system becomes excessive, the needle valve 1 will be immediately closed to restrict the admission of refrigerant to the system until the liquid refrigerant therein has time to vaporize.

The cylinders of the double suction pressure compressor are relatively so designed that a suitable suction pressure is maintained in the high suction line and the medium suction line. The temperature differential maintained between the high temperature and the low temperature coils by the weighted pressure reducing valve I3, is preferably selected or adjusted in accordance with the desired operating characteristics, and the compound compressor is preferably driven by an electric motor 54 which may be controlled automatically by means of a switch 56 actuated by a thermostatic device 56 associated with one of the coils. It will be understood that the motor switch may be actuated by a pressure responsive device associated with a suitable portion of the system or the motor may run continuously if desired.

In Fig. 21 have shown a second embodiment of my multipl mperature airtime-suct on refrigerating system which is simplified somewhat by eliminating the float valve and chamber from the system. The various elements of the system which are similar to the corresponding elements discussed with reference to Fig. 1 are designated by similar reference characters.

In the simplified embodiment of my system the medium suction line 21 from the second cylinder 28 of the compressor is connected through a vertical cylinder 6! thence by way of a conduit 62 to a line 63 which extends directly between the high temperature coil l and the weighted pressure reducing valve I3. The feed line 6 for supplying the system with liquid refrigerant from the condenser 4 extends through a pipe 64 which is coiled in close coupled heat exchange relation around the vertical cylinder 6| and thence extends to the needle valve 1.

In operation the liquid refrigerant which rises into the cylinder 6| in the medium suction line is heated by the liquid refrigerant which passes from the condenser in intimate heat exchange relation therewith. This vaporizes any liquid refrigerant rising in the medium pressure suction line 21 and prevents the liquid entering the compressor where it would cause knocking and eventually fracture the cylinder walls. Although I have disclosed my invention as speciflcally applied to a two temperature system it will be readily understood that the features of my invention are applicable to various systems in a manner which will be readily understood by those skilled in the art.

While it is necessary for the purpose of illustration to describe the several disclosed forms of my invention in detail, it will be apparent that the invention is not so limited, and that other forms and applications thereof, are embraced within the scope of the appended claims.

I claim as my invention-- 1. A refrigerating system comprising in combination a plurality of evaporators, means for withdrawing gaseous refrigerant from the evaporators condensing the same and conducting the condensed refrigerant to the evaporators, one of said evaporators being connected in series circuit relation with the other for receiving liquid refrigerant from the said other evaporator, each of said evaporators having a suction line connected with the flrst mentioned means, pressure responsive means responsive to the difference in pressures between said evaporators for causing refrigerant to be fed from said other evaporator to said one evaporator, means responsive to excess refrigerant from said other evaporator for by-passing the excess refrigerant around said pressure responsive means. for preventing liquid refrigerant from being conducted from the said other evaporator to the first mentioned means, a valve for controlling the flow of refrigerant from the flrst mentioned means to said evaporator. and means responsive to the condition at the outlet of said one evaporator for controlling said valve.

2. A refrigerating system comprising in combination a low temperature evaporator and a high temperature evaporator said low temperature evaporator being adapted to receive liquid refrigerant from the high temperature evaporator, a valve interposed between said evaporators, a suction line for each of said evaporators, means for withdrawing gaseous refrigerant from said evaporators and cooperating with said valve for maintaining different pressures in said evaporators, and a heat exchanger for applying heat aoea sae from a portion of the system to vaporize the excess of liquid refrigerant which is discharged from the outlet of said high temperature evaporator for preventing the conduction of liquid refrigerant from the high temperature evaporator to said withdrawing means.

3. A refrigerating system comprising in com bination a low temperature evaporator and a high temperature evaporator said low temperature evaporator being adapted to receive liquid refrigerant from the high temperature evaporator, a valve interposed between said evaporators, a suction line for each of said evaporators, means for withdrawing gaseous refrigerant from said evaporators, and cooperating with said valve for maintaining different pressures in said evaporaters, and means responsive to excess refrigerant from said high temperature evaporator for by-passing the excessrefrigerant around said valve, for preventing the conduction of liquid refrigerant from the high temperature evaporator to said withdrawing means.

i. A refrigerating system comprising in combination a low temperature evaporator and a high temperature evaporator said low temperature evaporator being adapted to receive liquid refrigerant from the high temperature evaporator, a valve interposed between said evaporators, means for withdrawing gaseous refrigerant from said evaporators, and cooperating with said valve for maintaining different pressures in said evaporators, a heat exchanger for applying heat from a portion of the system to vaporize the excess liquid refrigerant from the outlet of said high temperature evaporator, for preventing the conduction of liquid refrigerant from the high temperature evaporator to said withdrawing means, and means responsive to the condition of refrigerant at the outlet of the low temperature evaporator for controlling the flow of liquid refrigerant to the high pressure evaporator.

5. A refrigerating system comprising in combination a low temperature evaporator and a high temperature evaporator, said low temperture evaporator being adapted to receive liquid refrigerant from the high temperature evaporator, a valve interposed between said evaporators, a suction line for each of said evaporators, means for withdrawing gaseous refrigerant from said evaporators, and cooperating with said valve for maintaining diiferent pressures in said evaporators, means responsive to excess refrigerant from said high temperature evaporator for by-passing the excess refrigerant around said valve, for preventing the conduction of liquid refrigerant from the high temperature evaporator to said withdrawing means, and means responsive to the condition of refrigerant at the outlet of the low temperature evaporator for controlling the flow of liquid refrigerant to the high pressure evaporator.

6. In a multiple temperature refrigerating system the'combination of a high temperature coil, 2. low temperature coil, refrigerant condensing means, a liquid refrigerant feed line extending from said condensing means to said high temperature coil, a valve interposed in said feed line, pressure reducing means interconnected between said coils, a high suction line extending from said low temperature coil to said condensing means, means responsive to liquid in said suc tion line for closing the valve in said feed line, a medium suction line, means interconnecting said medium suction line between said high temperature coil and said pressure reducing means comprising a heat exchange device, and a second portion of said heat exchange device comprising conduit means connected in series in said feed line.

7. A refrigerating system comprising the combination of a plurality of refrigerant evaporotors, a refrigerant compressor, conduit means operatively connecting said evaporators in series relation with said compressor, means responsive to pressure only for controlling the flow of refrigerant between said evaporators, means responsive to liquid refrigerant only, and conduit means connecting said pressure responsive and liquid means in bypassing relation.

8. A refrigerating system comprising the combination of a plurality of refrigerant evaporators.

a refrigerant compressor, conduit means operativelyconnecting said evaporators in series relation with said compressor, means responsive to pressure only for controlling the flow of refrigerant between said evaporators, a float valve, conduit means connecting said float valve in bypassing relation around said means, and a suction conduit connected between the float chamber of said float valve and said compressor.

9. A refrigerating system comprising the combination of a plurality of refrigerant evaporators, a refrigerant compressor, conduit means operatively connecting said evaporators in series relation with said compressor, means responsive to pressure only for controlling the flow of refrigerant between said evaporators, a float valve, conduit means connecting said float valve in bypassing relation around said means, a suction conduit connected between the float chamber of said float valve and said compressor, and means responsive to liquid refrigerant from the outlet of the last evaporator for shutting ed the supply of refrigerant to the first evaporator.

10. A refrigerating system comprising, in combination, a plurality of liquid refrigerant evaporators connected in series, pressure difierential means between said evaporators for controlling the flow of liquid and gaseous refrigerant from one evaporator to another, and means for bypassing refrigerant from one evaporator to the other around said pressure diflerence means.

11. A refrigerating system, comprising in combination, a plurality of liquid refrigerant evaporators, means connecting said evaporators responsive to the pressure in one of said evaporators to control the flow of liquid and gaseous refrigerant to another evaporator, and means for by-passing refrigerant from one evaporator to the other around said means.

12. A refrigerating system comprising, in combination, a plurality of liquid refrigerant evaporators, a pressure difference device interconnecting said evaporators for controlling the flow of liquid and gaseous refrigerant from the first to a second evaporator, valve means associated with the outlet of the second evaporator for controlling the admission of liquid refrigerant to the first evaporator, and means for by-passing refrigerant around said pressure difference device.

LAWRENCE A. PHILIPP. 

